As a convent ional apparatus for producing ethanol, there has been known an apparatus that efficiently utilizes an expensive enzyme by separating, by means of distillation, a reaction liquid of saccharification fermentation from a fermentation product under such a condition as to prevent the deactivation of the enzyme and by performing the recycled use of the enzyme contained in a distillation residual in a saccharification fermentation process and/or a preliminary saccharification process. (See Patent Literature 1, for example).